The invention relates generally to using wireless signals to determine location and, more particularly, to using wireless signals to locate a mobile computer.
Many organizations today operate their own internal computer networks. Wireless communication is increasingly an important part of such networks. The advantages of wireless communication is that it allows a user to be mobile, and, for example carry his notebook or handheld computer from room to room and from building to building while maintaining connectivity to the organization""s network. The mobile user""s computer typically communicates with the network through a series of wireless access points distributed throughout the organization""s facility.
There are many applications in which determining the location of a mobile user is useful. For example, if an employee of a large corporation needs to print out a document, but finds himself in an unfamiliar building, he will have to walk around looking for the nearest printer and, once he finds it, determine the printer""s network name and select the printer on his screen. It would be very useful for the employee if he could simply send the document to xe2x80x9cthe nearest printer,xe2x80x9d have the network identify the nearest printer, automatically send the document there, and give directions to the user as to how to get to the printer.
The invention is generally directed to a method and system for determining the location of a mobile computer, in which the mobile computer establishes a wireless communication session with a wireless access point of a computer network. According to various embodiments of the invention, the location of each wireless access point is known and obtainable either from a database on the network or from the access points themselves. The strengths of wireless signals passing between the mobile computer and multiple wireless access points of the network, including the access point with which the mobile computer has established the session, are measured at multiple time intervals. The measurements may be taken at the mobile computer itself or at the wireless access points. The measured strength values are then weighted according to such factors as whether the mobile computer has already established a communication session with the access point from which the sample was taken, and how old the sample is. For each location, the weighted strength values obtained for access points in that location are summed. The location having the highest sum is deemed to be the location of the mobile computer.
In various embodiments of the invention, the location of each wireless access point and consequently, the location of the mobile computer may be expressed in a variety of ways. For example, the location of the mobile computer may be calculated and expressed as a physical location, relative to some reference point, or as part of a grid system established by the system administrator.
Additional features and advantages of the invention will be made apparent from the following detailed description of illustrative embodiments that proceeds with reference to the accompanying figures.